WO2018159662A1 - Compound, light emitting material and organic light emitting element - Google Patents

Abstract

A compound according to the present invention, which has a structure represented by general formula AA is useful as a light emitting material. In the general formula, at least one of R1-R9 represents a substituent; each of Y1-Y3 represents a methylene group, a carbonyl group, a thiocarbonyl group, an imino group, an oxygen atom, a sulfur atom or a sulfonyl group; and Z represents a nitrogen atom, a boron atom or a phosphine oxide group.

Description

COMPOUND, LIGHT EMITTING MATERIAL AND ORGANIC LIGHT EMITTING DEVICE

The present invention relates to a compound, a light emitting material composed of the compound, and an organic light emitting device using the compound.

Researches for increasing the light emission efficiency of organic light emitting devices such as organic electroluminescence devices (organic EL devices) are being actively conducted. In particular, various efforts have been made to increase the light emission efficiency by newly developing and combining electron transport materials, hole transport materials, light emitting materials, and the like constituting the organic electroluminescence element. Among them, research on organic electroluminescence devices using thermally activated delayed fluorescent materials can also be found.
Thermally activated delayed fluorescent material is the transition from excited triplet state to excited singlet state due to the absorption of thermal energy when transitioning to excited triplet state. It is a compound that emits fluorescence when returning to the back. The fluorescence due to such a route is called delayed fluorescence because it is observed later than the fluorescence from the excited singlet state (normal fluorescence) directly generated without passing through the reverse intersystem crossing. For example, in the current excitation of a compound, since the generation probability of an excited singlet state and an excited triplet state is 25%: 75%, there is a limit to the improvement of the light emission efficiency only with the fluorescence generated directly from the excited singlet state. is there. On the other hand, in the thermally activated delayed fluorescent material, the excited triplet state energy generated with a probability of 75% can also be effectively used for fluorescence emission, so that higher luminous efficiency can be expected.
As a conventional typical thermally activated delayed fluorescent material, a material including a structure in which a donor site (D) and an acceptor site (A) are bonded (DA type structure) is known (for example, non-patent document). 1-4). It is recognized that the donor site (D) and the acceptor site (A) are structurally twisted with each other in order to realize high luminous efficiency.

On the other hand, with respect to a compound having no structural twist between the donor site (D) and the acceptor site (A) and a compound not having a structure in which the donor site (D) and the acceptor site (A) are bonded, excellent emission characteristics. Research to achieve this has not been sufficiently advanced. Therefore, the present inventors have tackled the molecular design of the luminescent material from a new point of view, and have conducted intensive studies for the purpose of providing a new luminescent material.

As a result of diligent studies to achieve the above object, the present inventors have completed a new invention described below.
[1] A compound having a structure represented by the following general formula (1).

[In the general formula (1), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Y ¹ to Y ³ are each independently a substituted or unsubstituted methylene group (C (R ¹⁰ ) (R ¹¹ ); R ¹⁰ and R ¹¹ each independently represents a hydrogen atom or a substituent), a carbonyl group (C═ O), a thiocarbonyl group (C═S), a substituted or unsubstituted imino group (N (R ¹² ); R ¹² represents a hydrogen atom or a substituent), an oxygen atom, a sulfur atom, or a sulfonyl group (SO ₂ ). Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
[2] The compound according to [1], wherein Z in the general formula (1) is a nitrogen atom.
[3] The compound according to [1] or [2], wherein Y ¹ to Y ³ in the general formula (1) are a carbonyl group or a dialkylmethylene group [4] R ² in the general formula (1) is substituted. The compound according to any one of [1] to [3], which is a group.
[5] The compound according to [4], wherein R ² in the general formula (1) is a donor group.
[6] The compound according to [4], wherein R ² in the general formula (1) is an acceptor group.
[7] The compound according to any one of [4] to [6], which can form a hydrogen bond between R ¹ and R ² in the general formula (1).
[8] The compound according to [7], wherein a hydrogen bond can be formed between R ² and R ³ in the general formula (1).
[9] The compound according to any one of [1] to [8], which has a line symmetry axis in the molecule.
[10] The compound according to any one of [1] to [9], which is represented by the following general formula (2).

[In the general formula (2), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. R ¹¹ to R ¹⁶ each independently represents a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
[11] The compound according to [10], wherein R ² in the general formula (2) is a substituted or unsubstituted heteroaryl group.
[12] The compound according to [11], wherein the heteroaryl group contains a nitrogen atom as a ring skeleton constituent atom.
[13] The compound according to [12], wherein at least one of the ring skeleton constituent atoms adjacent to the atom involved in the bonding of the heteroaryl group is a nitrogen atom.
[14] The compound according to [13], wherein R ¹ in the general formula (2) is a hydrogen atom.
[15] The compound according to [12], wherein each of the ring skeleton constituent atoms adjacent to the atom involved in bonding of the heteroaryl group is a nitrogen atom.
[16] The compound according to [15], wherein the heteroaryl group is a substituted or unsubstituted triazinyl group.
[17] The compound according to [16], wherein the heteroaryl group is a substituted or unsubstituted diaryltriazinyl group.
[18] The compound according to any one of [15] to [17], wherein R ¹ and R ³ in the general formula (2) are hydrogen atoms.
[19] In the above [11] to [18], at least one of R ⁴ to R ⁶ and at least one of R ⁷ to R ^{9 in} the general formula (2) is a group containing a diarylamino structure or a carbazole ring. The compound according to any one of the above.
[20] The compound according to [19], wherein R ⁵ and R ⁸ in the general formula (2) are a group containing a diarylamino structure or a carbazole ring.
[21] At least one of R ⁴ to R ⁶ and at least one of R ⁷ to R ^{9 in} the general formula (2) is a group having a structure represented by the following general formula (4). [11] The compound according to any one of [20] to [20].

[In the general formula (4), R ²¹ to R ³⁰ each independently represents a hydrogen atom or a substituent. R ²⁵ and R ²⁶ may be linked to each other to form a single bond or a linking group. L represents a single bond or a substituted or unsubstituted arylene group. * Indicates a binding position. ]
[22] The compound according to [21], wherein R ²⁵ and R ²⁶ in the general formula (4) are not linked to each other.
[23] The compound according to [21] or [22], wherein at least one of R ²³ and R ²⁸ in the general formula (4) is a substituent.
[24] The compound according to any one of [21] to [23], wherein L in the general formula (4) is a single bond.
[25] The compound according to any one of [10] to [24], wherein R ¹¹ to R ¹⁶ in the general formula (2) are each independently a substituted or unsubstituted alkyl group.
[26] The compound according to [25], wherein R ¹¹ to R ¹⁶ in the general formula (2) are methyl groups.
[27] The compound according to any one of [1] to [9], which is represented by the following general formula (3).

[In the general formula (3), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
[28] The compound according to [27], wherein at least one of R ¹ to R ⁹ in the general formula (3) is a donor group.
[29] The compound according to [27] or [28], wherein R ² in the general formula (3) is a group containing a diarylamino structure or a carbazole ring.
[30] In any one of [27] to [29], at least one of R ¹ to R ⁹ in the general formula (3) is a group having a structure represented by the following general formula (4): The described compound.

[In the general formula (4), R ²¹ to R ³⁰ each independently represents a hydrogen atom or a substituent. R ²⁵ and R ²⁶ may be linked to each other to form a single bond or a linking group. L represents a single bond or a substituted or unsubstituted arylene group. * Indicates a binding position. ]
[31] The compound according to claim 30, wherein R ²⁵ and R ²⁶ in formula (4) are not linked to each other.
[32] The compound according to claim 30, wherein R ²⁵ and R ²⁶ in formula (4) are linked to each other to form a single bond.
[33] The compound according to any one of [30] to [32], wherein L in the general formula (4) is a substituted or unsubstituted phenylene group.
[34] The compound according to any one of [30] to [32], wherein L in the general formula (4) is a single bond.
[35] The compound according to any one of [30] to [34], wherein R ² in the general formula (3) is a group represented by the general formula (4).
[36] The compound according to any one of [1] to [35], which emits delayed fluorescence.
[37] A light emitting material comprising a compound having a structure represented by the general formula (1).
[38] An organic light-emitting device comprising a compound having a structure represented by the general formula (1).
[39] The organic light-emitting element according to [38], wherein the element is an organic electroluminescence element.
[40] The organic light-emitting device according to [38] or [39], which emits delayed fluorescence.

It is a schematic sectional drawing which shows the layer structural example of an organic electroluminescent element.

Hereinafter, the contents of the present invention will be described in detail. The description of the constituent elements described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. In addition, the isotope species of the hydrogen atom present in the molecule of the compound used in the present invention is not particularly limited. For example, all the hydrogen atoms in the molecule may be ¹ H, or a part or all of the hydrogen atoms are ² H. (Deuterium D) may be used.
In addition, the entire description of the specification of Japanese Patent Application No. 2017-37588 is cited herein as part of the present application.

[Compound represented by general formula (1)]

The compound having the structure represented by the general formula (1) according to the present invention will be described.
In the general formula (1), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent. Examples of the substituent that R ¹ to R ⁹ can take include, for example, a hydroxy group, a halogen atom, a cyano group, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, An alkyl-substituted amino group having 1 to 20 carbon atoms, an aryl-substituted amino group having 12 to 40 carbon atoms, an acyl group having 2 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, Substituted or unsubstituted carbazolyl group having 12 to 40 carbon atoms, alkenyl group having 2 to 10 carbon atoms, alkynyl group having 2 to 10 carbon atoms, alkoxycarbonyl group having 2 to 10 carbon atoms, alkylsulfonyl having 1 to 10 carbon atoms Group, haloalkyl group having 1 to 10 carbon atoms, amide group, alkylamide group having 2 to 10 carbon atoms, trialkylsilyl group having 3 to 20 carbon atoms, tria having 4 to 20 carbon atoms Kill silylalkyl group, trialkylsilyl alkenyl group having 5 to 20 carbon atoms, and the like trialkylsilyl alkynyl group and a nitro group having 5 to 20 carbon atoms. Among these specific examples, those that can be substituted with a substituent may be further substituted. More preferred substituents are a halogen atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 40 carbon atoms, carbon A substituted or unsubstituted heteroaryl group having 3 to 40 carbon atoms, a substituted or unsubstituted dialkylamino group having 1 to 10 carbon atoms, a substituted or unsubstituted diarylamino group having 12 to 40 carbon atoms, and 12 to 40 carbon atoms A substituted or unsubstituted carbazolyl group; More preferred substituents are a fluorine atom, a chlorine atom, a cyano group, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, and a substituted group having 1 to 10 carbon atoms. Or an unsubstituted dialkylamino group, a substituted or unsubstituted diarylamino group having 12 to 40 carbon atoms, a substituted or unsubstituted aryl group having 6 to 15 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms It is a group.

At least one of R ¹ to R ⁹ in the general formula (1) represents a substituent. Among these, it is preferable that 1 to 3 selected from R ² , R ⁵ and R ⁸ are substituents. In addition, at least one substituent is preferably a donor group or an acceptor group.
In the present specification, the “donor group” means a group having a Hammett σ _p ⁺ value of less than 0. Examples of the “donor group” that can be employed in the present specification include those having Hammett's σ _p ⁺ value of less than −0.15, those of less than −0.3, those of −0.45 or less, − It is possible to adopt one that is 0.6 or less. Further, as the “donor group” that can be adopted in the present specification, for example, those having Hammett's σ _p ⁺ value of −2 or more and those of −1 or more can be adopted.
In the present specification, the “acceptor group” means a group having a Hammett σ _p ⁺ value larger than 0. Examples of the “acceptor group” that can be adopted in the present specification include those having Hammett's σ _p ⁺ value of 0.15 or more, those of 0.3 or more, those of 0.45 or more, and 0.6 or more. It is possible to adopt what is. Further, as the “acceptor group” that can be adopted in the present specification, for example, those having Hammett's σ _p ⁺ value of 2 or less and those of 1 or less can be adopted.
The “Hammett σ _p ⁺ value” in the present invention is L. P. Proposed by Hammett, it quantifies the effect of substituents on the reaction rate or equilibrium of para-substituted benzene derivatives. Specifically, the following formula is established between the substituent in the para-substituted benzene derivative and the reaction rate constant or equilibrium constant:

This is a constant (σ _p ) peculiar to the substituent in. In the above formula, k is a rate constant of a benzene derivative having no substituent, k ₀ is a rate constant of a benzene derivative substituted with a substituent, K is an equilibrium constant of a benzene derivative having no substituent, and K ₀ is a substituent. The equilibrium constant of the benzene derivative substituted with ρ, ρ represents the reaction constant determined by the type and conditions of the reaction. For a description of Hammett's σ _p value and the numerical value of each substituent, refer to JADean edited by “Lange's Handbook of Chemistry 13th edition”, 1985, pages 3-132 to 3-137, McGrow-Hill.

Y ¹ to Y ³ in the general formula (1) are each independently a substituted or unsubstituted methylene group (C (R ¹⁰ ) (R ¹¹ ); R ¹⁰ and R ¹¹ each independently represents a hydrogen atom or a substituent) , A carbonyl group (C═O), a thiocarbonyl group (C═S), a substituted or unsubstituted imino group (N (R ¹² ); R ¹² represents a hydrogen atom or a substituent), an oxygen atom, a sulfur atom, Or represents a sulfonyl group (SO ₂ ). Y ¹ to Y ³ may be the same or different, but it is preferable that all of Y ¹ to Y ³ are the same. R ¹⁰ and R ¹¹ of C (R ¹⁰ ) (R ¹¹ ), which is a methylene group that Y ¹ to Y ³ can take, are preferably each independently a substituent, and are a substituted or unsubstituted alkyl group. Is more preferable, and a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms is even more preferable. Preferably R ¹² in Y 1 ^~ Y ³ is imino group which may take N (R ¹²⁾ is a substituted group, more preferably a substituted or unsubstituted alkyl group, substituted with 1 to 3 carbon atoms Or it is still more preferable that it is an unsubstituted alkyl group.

Z in the general formula (1) represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O).

The compound represented by the general formula (1) may have a symmetric structure. For example, a compound having a line symmetrical structure can be preferably employed. A compound having a rotationally symmetric structure with Z as the central atom as the central axis can also be preferably employed.
The compound represented by the general formula (1) is preferably a compound capable of forming a hydrogen bond between R ¹ and R ² . In addition, the compound represented by the general formula (1) is more capable of forming a hydrogen bond between R ¹ and R ² and also forming a hydrogen bond between R ² and R ^3. preferable. Such a hydrogen bond is preferably one that can be formed between R ⁴ and R ⁵ , between R ⁵ and R ⁶ , between R ⁷ and R ⁸ , and between R ⁸ and R ⁹ . A hydrogen bond can be formed, for example, between a hydrogen atom and a nitrogen atom. It can be illustrated.

As the compound represented by the general formula (1), a compound represented by the general formula (2) can be preferably employed.

In the general formula (2), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. R ¹¹ to R ¹⁶ each independently represents a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). For the description of the substituents that can be adopted by R ¹ to R ^{9 in} the general formula (2), preferred ranges, and specific examples, the corresponding description about the general formula (1) can be referred to.
R ² in the general formula (2) is preferably a substituted or unsubstituted heteroaryl group, more preferably a nitrogen atom as a ring skeleton constituent atom, and adjacent to an atom involved in bonding of the heteroaryl group. More preferably, the ring skeleton constituent atoms are all nitrogen atoms. Specific examples of the heteroaryl group include a substituted or unsubstituted triazinyl group, and preferred examples thereof include a substituted or unsubstituted diaryltriazinyl group. When the ring skeleton constituent atoms adjacent to the atoms involved in the bonding of the heteroaryl group are all nitrogen atoms, a hydrogen bond can be formed if R ¹ or R ³ is a hydrogen atom.
Further, when R ² in the general formula (2) is a substituted or unsubstituted heteroaryl group, all of R ¹ and R ³ to R ⁹ may be hydrogen atoms, or at least one of them is a substituent. However, it is preferred that at least one of R ⁴ to R ⁶ and R ⁷ to R ⁹ is a group containing a diarylamino structure or a carbazole ring, and at least one of R ⁴ to R ⁶ and R ⁷ to R ⁹ More preferably, at least one of is a group containing a diarylamino structure or a carbazole ring, and R ⁵ and R ⁸ are more preferably a group containing a diarylamino structure or a carbazole ring. For the description and preferred range of the group containing a diarylamino structure or a carbazole ring, the explanation and preferred range of the group containing a diarylamino structure and the group containing a carbazole ring which can be taken by R ¹ to R ^{9 in} the general formula (3) You can refer to it. When the group containing the diarylamino structure in the general formula (2) is a group represented by the general formula (4), R ²⁵ and R ²⁶ are preferably not connected to each other, and at least one of R ²³ and R ²⁸ Is preferably a substituent, L is preferably a single bond, and more preferably has all of these preferred structures. Further, the substituent in R ²³ and R ²⁸ is preferably a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms. R ¹¹ to R ¹⁶ in the general formula (2) are preferably each independently a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, More preferably, it is an unsubstituted alkyl group having 1 to 3 carbon atoms. For example, a methyl group and an ethyl group can be mentioned.

As the compound represented by the general formula (1), a compound represented by the general formula (3) can also be preferably employed.

In the general formula (3), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). For the explanation and preferred ranges and specific examples of the substituents that can be adopted by R ¹ to R ^{9 in} the general formula (3), the corresponding description about the general formula (1) can be referred to. In general formula (3), at least one of R ¹ to R ⁹ is preferably a donor group.

In general formula (3), at least one of R ¹ to R ⁹ is preferably a group containing a diarylamino structure or a group containing a carbazole ring, and R ² is a group containing a diarylamino structure or a group containing a carbazole ring. More preferably. Here, the “diarylamino structure” means both a diarylamino group and a heteroaromatic ring structure in which the aryl groups of the diarylamino group are linked by a single bond or a linking group to form a heterocyclic ring. And The aromatic ring constituting each aryl group of the diarylamino structure may be a single ring, a condensed ring in which two or more aromatic rings are condensed, or a linked ring in which two or more aromatic rings are connected. Good. When two or more aromatic rings are linked, they may be linked in a straight chain or may be branched. The number of carbon atoms in the aromatic ring constituting each aryl group of the diarylamino structure is preferably 6-22, more preferably 6-18, still more preferably 6-14, and 6-10. Even more preferably. Specific examples of each aryl group include a phenyl group, a naphthyl group, and a biphenyl group, and a phenyl group is preferable. For the explanation and preferred range of the substituent when the diarylamino structure has a substituent, reference can be made to the explanation and preferred range of the substituent that can be taken by R ²¹ to R ^{30 in} the following general formula (4). Regarding the explanation and preferred range of the linking group for linking aryl groups when the diarylamino structure is the above heteroaromatic ring structure, R ²⁵ and R ^{26 in} the following general formula (4) are linked to each other to form a linking group. Reference can be made to the description and preferred range of the linking group when it is formed. Of the groups containing a diarylamino structure, when each aryl group of the diarylamino structure is a phenyl group, and the phenyl groups are linked by a single bond, the group containing the diarylamino structure has the above carbazole ring. Corresponds to the containing group.
In the group containing a diarylamino structure, the nitrogen atom to which each aryl group of the diarylamino structure is bonded may be bonded to the benzene ring in the general formula (3) by a single bond or connected by a linking group. Also good. That is, the group containing a diarylamino structure may contain a linking group that connects the diarylamino structure to a benzene ring. The linking group for linking the diarylamino structure to the benzene ring is not particularly limited, but is preferably a substituted or unsubstituted arylene group. For the description and preferred range and specific examples of the substituted or unsubstituted arylene group, the description and preferred range and specific examples of the substituted or unsubstituted arylene group in L of the following general formula (4) can be referred to.

The group containing a diarylamino structure is particularly preferably a group having a structure represented by the general formula (4).

In the general formula (4), R ²¹ to R ³⁰ each independently represents a hydrogen atom or a substituent. The number of substituents is not particularly limited, and all of R ²¹ to R ³⁰ may be unsubstituted (that is, hydrogen atoms). When two or more of R ²¹ to R ³⁰ are substituents, the plurality of substituents may be the same as or different from each other.
Examples of the substituent that R ²¹ to R ³⁰ can take include, for example, a hydroxy group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, and 1 to 20 alkyl-substituted amino groups, aryl-substituted amino groups having 12 to 40 carbon atoms, aryl groups having 6 to 40 carbon atoms, heteroaryl groups having 3 to 40 carbon atoms, alkenyl groups having 2 to 10 carbon atoms, and 2 to And an alkynyl group having 10 to 20 carbon atoms, an alkylamide group having 2 to 20 carbon atoms, an arylamide group having 7 to 21 carbon atoms, and a trialkylsilyl group having 3 to 20 carbon atoms. Among these specific examples, those that can be substituted with a substituent may be further substituted. More preferred substituents are alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkyl-substituted amino groups having 1 to 20 carbon atoms, and 12 to 40 carbon atoms. An aryl-substituted amino group, an aryl group having 6 to 40 carbon atoms, and a heteroaryl group having 3 to 40 carbon atoms.

R ²⁵ and R ²⁶ may be linked to each other to form a single bond or a linking group. Among the groups represented by the general formula (4), R ²⁵ and R ²⁶ are not connected to each other, R ²⁵ and R ²⁶ are connected to each other to form a single bond, or R ²⁵ And R ²⁶ are preferably bonded to each other to form a linking group having a linking chain length of 1 atom, R ²⁵ and R ²⁶ are not connected to each other, and R ²⁵ and R ²⁶ are connected to each other. What forms the bond is more preferable. When R ²⁵ and R ²⁶ are bonded to each other to form a linking group having a linking chain length of 1 atom, the cyclic structure formed as a result of the bonding of R ²⁵ and R ²⁶ to each other is a 6-membered ring. Specific examples of the linking group formed by bonding R ²⁵ and R ²⁶ to each other are represented by —O—, —S—, —N (R ⁹¹ ) — or —C (R ⁹² ) (R ⁹³ ) —. A linking group. Here, R ⁹¹ to R ⁹³ each independently represents a hydrogen atom or a substituent. Examples of the substituent that R ⁹¹ can take include an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 40 carbon atoms, and a heteroaryl group having 3 to 40 carbon atoms. Examples of the substituent that R ⁹² and R ⁹³ can take are each independently a hydroxy group, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, An alkyl-substituted amino group having 1 to 20 carbon atoms, an aryl-substituted amino group having 12 to 40 carbon atoms, an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, Examples thereof include an alkynyl group having 2 to 10 carbon atoms, an alkylamide group having 2 to 20 carbon atoms, an arylamide group having 7 to 21 carbon atoms, and a trialkylsilyl group having 3 to 20 carbon atoms.

L represents a single bond or a substituted or unsubstituted arylene group. * Indicates a binding position. For the explanation and preferred range of the aromatic ring constituting the arylene group in L, the explanation and preferred range for the aromatic ring constituting each aryl of the diarylamino structure can be referred to, and the arylene group has a substituent. For the explanation and preferred ranges of the substituents in the case, and specific examples, the explanations and preferred ranges of the substituents that can be taken by the above R ²¹ to R ³⁰ can be referred to. Specific examples of the substituted or unsubstituted arylene group in L include a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, and a substituted or unsubstituted biphenyl-diyl group. A phenylene group is preferred.

Hereinafter, specific examples of the compound represented by the general formula (1) are illustrated. However, the compound represented by the general formula (1) that can be used in the present invention should not be limitedly interpreted by these specific examples.

In the compound represented by the general formula (1), the difference ΔE _ST between the lowest excited singlet energy level E _S1 and the lowest excited triplet energy level E _T1 in a state doped in mCBP is 0.4 eV or less. Is preferred,
More preferably, it is 0.2 eV or less, and more preferably 0.1 eV or less. Method of measuring the Delta] E _ST, it is possible to see the Examples section.

The compound represented by the general formula (1) can emit delayed fluorescence. Therefore, the present invention includes an invention of a delayed phosphor having a structure represented by the general formula (1).

The molecular weight of the compound represented by the general formula (1) is, for example, 1500 or less when the organic layer containing the compound represented by the general formula (1) is intended to be formed by vapor deposition. Preferably, it is preferably 1200 or less, more preferably 1000 or less, and even more preferably 800 or less. The lower limit of the molecular weight is the smallest molecular weight that the general formula (1) can take.
The compound represented by the general formula (1) may be formed by a coating method regardless of the molecular weight. If a coating method is used, a film can be formed even with a compound having a relatively large molecular weight.

Further, the compound that emits delayed fluorescence and is capable of intramolecular proton transfer may be a polymer obtained by polymerizing a polymerizable monomer that emits delayed fluorescence and is capable of intramolecular proton transfer.
For example, it is considered that a polymer obtained by polymerizing a polymerizable group in advance in the structure represented by the general formula (1) is used as a material for the organic light emitting device. It is done. Specifically, a monomer containing a polymerizable functional group is prepared in any ^one of R ¹ to R ⁹ or Y ¹ to Y ^{3 in} the general formula (1), and this is polymerized alone or together with other monomers. It is conceivable to obtain a polymer having a repeating unit by copolymerization and use the polymer as a material for an organic light-emitting device. Alternatively, it is also conceivable that dimers and trimers are obtained by coupling compounds having a structure represented by the general formula (1) and used as materials for organic light emitting devices.

As an example of the polymer having a repeating unit including the structure represented by the general formula (1), a polymer including a structure represented by the following general formula (11) or (12) can be given.

In the general formula (11) or (12), Q represents a group including the structure represented by the general formula (1), and L ¹ and L ² represent a linking group. The linking group preferably has 0 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and still more preferably 2 to 10 carbon atoms. And preferably has a structure represented by - linking group ^-X 11 ^{-L 11.} Here, X ¹¹ represents an oxygen atom or a sulfur atom, and is preferably an oxygen atom. L ¹¹ represents a linking group, and is preferably a substituted or unsubstituted alkylene group, or a substituted or unsubstituted arylene group, and is a substituted or unsubstituted alkylene group having 1 to 10 carbon atoms, or a substituted or unsubstituted group A phenylene group is more preferable.
In General Formula (11) or (12), R ¹⁰¹ , R ¹⁰² , R ¹⁰³ and R ¹⁰⁴ each independently represent a substituent. Preferably, it is a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a halogen atom, more preferably an unsubstituted alkyl group having 1 to 3 carbon atoms. An unsubstituted alkoxy group having 1 to 3 carbon atoms, a fluorine atom, and a chlorine atom, and more preferably an unsubstituted alkyl group having 1 to 3 carbon atoms and an unsubstituted alkoxy group having 1 to 3 carbon atoms.
The linking group represented by L ¹ and L ² can be bonded to any of R ¹ to R ⁹ or Y ¹ to Y ³ in the structure of the general formula (1) constituting Q. Two or more linking groups may be linked to one Q to form a crosslinked structure or a network structure.

Specific examples of the structure of the repeating unit include structures represented by the following formulas (13) to (16).

A polymer having a repeating unit containing these formulas (13) to (16) has a hydroxy group introduced into any of R ¹ to R ⁹ or Y ¹ to Y ³ in the structure of the general formula (1). Then, it can be synthesized by reacting the following compound as a linker to introduce a polymerizable group and polymerizing the polymerizable group.

The polymer containing the structure represented by the general formula (1) in the molecule may be a polymer composed only of repeating units having the structure represented by the general formula (1), or other structures may be used. It may be a polymer containing repeating units. The repeating unit having a structure represented by the general formula (1) contained in the polymer may be a single type or two or more types. Examples of the repeating unit not having the structure represented by the general formula (1) include those derived from monomers used in ordinary copolymerization. Examples thereof include a repeating unit derived from a monomer having an ethylenically unsaturated bond such as ethylene and styrene.

[Synthesis Method of Compound Represented by General Formula (1)]
The method for synthesizing the compound represented by the general formula (1) is not particularly limited. For example, the synthesis of compounds wherein R ² is a substituent of the general formula (1) may be R ² in the general formula (1) reacting a compound a compound represented by R ^2-X is a hydrogen atom or, R ² in the general formula (1) can be synthesized by reacting a compound is a halogen atom with a compound represented by R ² over H. Here, X is a halogen atom. The halogen atom is preferably a chlorine atom, a bromine atom or an iodine atom. The details of this reaction can be referred to the synthesis examples described later. The compound represented by the general formula (1) can also be synthesized by combining other known synthesis reactions.

[Organic light emitting device]
In the organic light emitting device of the present invention, a compound that emits delayed fluorescence and is capable of intramolecular proton transfer is used. A compound that emits delayed fluorescence and is capable of intramolecular proton transfer exhibits a sufficiently high quantum yield for practical use, and can be effectively used as a light-emitting material of an organic light-emitting device. Further, a compound that emits delayed fluorescence and is capable of intramolecular proton transfer can also be used as a host or assist dopant in an organic light-emitting device. For example, an organic light-emitting device using a compound that emits delayed fluorescence and is capable of intramolecular proton transfer as a light-emitting material has a feature of high luminous efficiency because this compound functions as a delayed fluorescent material. The principle will be described below by taking an organic electroluminescence element as an example.

In the organic electroluminescence element, carriers are injected into the light emitting material from both positive and negative electrodes to generate an excited light emitting material and emit light. In general, in the case of a carrier injection type organic electroluminescence element, 25% of the generated excitons are excited to the excited singlet state, and the remaining 75% are excited to the excited triplet state. Therefore, the use efficiency of energy is higher when phosphorescence, which is light emission from an excited triplet state, is used. However, since the excited triplet state has a long lifetime, energy saturation occurs due to saturation of the excited state and interaction with excitons in the excited triplet state, and in general, the quantum yield of phosphorescence is often not high. On the other hand, delayed fluorescent materials, after energy transition to an excited triplet state due to intersystem crossing, etc., are then crossed back to an excited singlet state due to triplet-triplet annihilation or absorption of thermal energy, and emit fluorescence. To do. In the organic electroluminescence device, it is considered that a thermally activated delayed fluorescent material by absorption of thermal energy is particularly useful. When a delayed fluorescent material is used for the organic electroluminescence element, excitons in the excited singlet state emit fluorescence as usual. On the other hand, excitons in the excited triplet state absorb the heat of the outside air and the heat generated by the device, and cross the terms into the excited singlet to emit fluorescence. At this time, since the light is emitted from the excited singlet, the light is emitted at the same wavelength as the fluorescence, but the light lifetime (luminescence lifetime) generated by the reverse intersystem crossing from the excited triplet state to the excited singlet state is normal. Since the fluorescence becomes longer than the fluorescence and phosphorescence, it is observed as fluorescence delayed from these. This can be defined as delayed fluorescence. If such a heat-activated exciton transfer mechanism is used, the ratio of the compound in an excited singlet state, which normally generated only 25%, is increased to 25% or more by absorbing thermal energy after carrier injection. It can be raised. If a compound that emits strong fluorescence and delayed fluorescence even at a low temperature of less than 100 ° C is used, the heat of the device will sufficiently cause intersystem crossing from the excited triplet state to the excited singlet state and emit delayed fluorescence. Efficiency can be improved dramatically.

By using a compound that emits delayed fluorescence and allows intramolecular proton transfer as the light emitting material of the light emitting layer, excellent organic light emission such as organic photoluminescence device (organic PL device) and organic electroluminescence device (organic EL device) An element can be provided. The organic photoluminescence element has a structure in which at least a light emitting layer is formed on a substrate. The organic electroluminescence element has a structure in which at least an anode, a cathode, and an organic layer are formed between the anode and the cathode. The organic layer includes at least a light emitting layer, and may consist of only the light emitting layer, or may have one or more organic layers in addition to the light emitting layer. Examples of such other organic layers include a hole transport layer, a hole injection layer, an electron blocking layer, a hole blocking layer, an electron injection layer, an electron transport layer, and an exciton blocking layer. The hole transport layer may be a hole injection / transport layer having a hole injection function, and the electron transport layer may be an electron injection / transport layer having an electron injection function. A specific example of the structure of an organic electroluminescence element is shown in FIG. In FIG. 1, 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, 5 is a light emitting layer, 6 is an electron transport layer, and 7 is a cathode.
Below, each member and each layer of an organic electroluminescent element are demonstrated. In addition, description of a board | substrate and a light emitting layer corresponds also to the board | substrate and light emitting layer of an organic photo-luminescence element.

(substrate)
The organic electroluminescence device of the present invention is preferably supported on a substrate. The substrate is not particularly limited and may be any substrate conventionally used for organic electroluminescence elements. For example, a substrate made of glass, transparent plastic, quartz, silicon, or the like can be used.

(anode)
As the anode in the organic electroluminescence element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by vapor deposition or sputtering of these electrode materials, and a pattern of a desired shape may be formed by photolithography, or when pattern accuracy is not so high (about 100 μm or more) ), A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Or when using the material which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

(cathode)
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic electroluminescence element is transparent or translucent, the emission luminance is advantageously improved.
In addition, by using the conductive transparent material mentioned in the description of the anode as a cathode, a transparent or semi-transparent cathode can be produced. By applying this, an element in which both the anode and the cathode are transparent is used. Can be produced.

(Light emitting layer)
The light emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from each of the anode and the cathode, and the light emitting material may be used alone for the light emitting layer. , Preferably including a luminescent material and a host material. As the luminescent material, one or more selected from a group of compounds that emit delayed fluorescence and are capable of intramolecular proton transfer can be used. In order for the organic electroluminescent device and the organic photoluminescent device of the present invention to exhibit high luminous efficiency, it is important to confine singlet excitons and triplet excitons generated in the light emitting material in the light emitting material. Therefore, it is preferable to use a host material in addition to the light emitting material in the light emitting layer. As the host material, an organic compound in which at least one of excited singlet energy and excited triplet energy has a value higher than that of the light-emitting material can be used. As a result, singlet excitons and triplet excitons generated in the light emitting material can be confined in the molecule of the light emitting material, and the light emission efficiency can be sufficiently extracted. However, even if singlet excitons and triplet excitons cannot be sufficiently confined, there are cases where high luminous efficiency can be obtained, so that host materials that can achieve high luminous efficiency are particularly limited. And can be used in the present invention. In the organic light-emitting device or organic electroluminescence device of the present invention, light emission is generated from a light-emitting material (compound that emits delayed fluorescence and is capable of intramolecular proton transfer) contained in the light-emitting layer. This emission includes both fluorescence and delayed fluorescence. However, light emission from the host material may be partly or partly emitted.
When a host material is used, the amount of a compound that is a light emitting material, that is, a compound that emits delayed fluorescence and capable of intramolecular proton transfer is preferably 0.1% by weight or more. It is more preferably at least wt%, more preferably at most 50 wt%, more preferably at most 20 wt%, and even more preferably at most 10 wt%.
The host material in the light-emitting layer is preferably an organic compound that has a hole transporting ability and an electron transporting ability, prevents the emission of longer wavelengths, and has a high glass transition temperature.

(Injection layer)
The injection layer is a layer provided between the electrode and the organic layer for lowering the driving voltage and improving the luminance of light emission. There are a hole injection layer and an electron injection layer, and between the anode and the light emitting layer or the hole transport layer. Further, it may be present between the cathode and the light emitting layer or the electron transport layer. The injection layer can be provided as necessary.

(Blocking layer)
The blocking layer is a layer that can prevent diffusion of charges (electrons or holes) and / or excitons existing in the light emitting layer to the outside of the light emitting layer. The electron blocking layer can be disposed between the light emitting layer and the hole transport layer and blocks electrons from passing through the light emitting layer toward the hole transport layer. Similarly, a hole blocking layer can be disposed between the light emitting layer and the electron transporting layer to prevent holes from passing through the light emitting layer toward the electron transporting layer. The blocking layer can also be used to block excitons from diffusing outside the light emitting layer. That is, each of the electron blocking layer and the hole blocking layer can also function as an exciton blocking layer. The term “electron blocking layer” or “exciton blocking layer” as used herein is used in the sense of including a layer having the functions of an electron blocking layer and an exciton blocking layer in one layer.

(Hole blocking layer)
The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer has a role of blocking holes from reaching the electron transport layer while transporting electrons, thereby improving the recombination probability of electrons and holes in the light emitting layer. As the material for the hole blocking layer, the material for the electron transport layer described later can be used as necessary.

(Electron blocking layer)
The electron blocking layer has a function of transporting holes in a broad sense. The electron blocking layer has a role to block electrons from reaching the hole transport layer while transporting holes, thereby improving the probability of recombination of electrons and holes in the light emitting layer. .

(Exciton blocking layer)
The exciton blocking layer is a layer for preventing excitons generated by recombination of holes and electrons in the light emitting layer from diffusing into the charge transport layer. It becomes possible to efficiently confine in the light emitting layer, and the light emission efficiency of the device can be improved. The exciton blocking layer can be inserted on either the anode side or the cathode side adjacent to the light emitting layer, or both can be inserted simultaneously. That is, when the exciton blocking layer is provided on the anode side, the layer can be inserted adjacent to the light emitting layer between the hole transport layer and the light emitting layer, and when inserted on the cathode side, the light emitting layer and the cathode Between the luminescent layer and the light-emitting layer. Further, a hole injection layer, an electron blocking layer, or the like can be provided between the anode and the exciton blocking layer adjacent to the anode side of the light emitting layer, and the excitation adjacent to the cathode and the cathode side of the light emitting layer can be provided. Between the child blocking layer, an electron injection layer, an electron transport layer, a hole blocking layer, and the like can be provided. When the blocking layer is disposed, at least one of the excited singlet energy and the excited triplet energy of the material used as the blocking layer is preferably higher than the excited singlet energy and the excited triplet energy of the light emitting material.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes, and the hole transport layer can be provided as a single layer or a plurality of layers.
The hole transport material has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. Known hole transport materials that can be used include, for example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, carbazole derivatives, indolocarbazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, Examples include amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers. An aromatic tertiary amine compound and an styrylamine compound are preferably used, and an aromatic tertiary amine compound is more preferably used.

(Electron transport layer)
The electron transport layer is made of a material having a function of transporting electrons, and the electron transport layer can be provided as a single layer or a plurality of layers.
The electron transport material (which may also serve as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer. Examples of the electron transport layer that can be used include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide oxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

When producing an organic electroluminescence device, not only a compound that emits delayed fluorescence and capable of intramolecular proton transfer may be used for a light emitting layer, but also for a layer other than the light emitting layer. At that time, the compound that emits delayed fluorescence contained in each layer and is capable of intramolecular proton transfer may be the same or different depending on whether it is used for the light-emitting layer or a layer other than the light-emitting layer. Good. For example, the above injection layer, blocking layer, hole blocking layer, electron blocking layer, exciton blocking layer, hole transport layer, electron transport layer, etc. can emit delayed fluorescence and allow intramolecular proton transfer May be used. The method for forming these layers is not particularly limited, and the layer may be formed by either a dry process or a wet process.

Specific examples of preferable materials that can be used for the organic electroluminescence element are shown below. However, the material that can be used in the present invention is not limited to the following exemplary compounds. Moreover, even if it is a compound illustrated as a material which has a specific function, it can also be diverted as a material which has another function.

First, preferred compounds that can also be used as a host material for the light emitting layer are listed.

Next, preferred examples of compounds that can be used as the hole injection material are given.

Next, preferred examples of compounds that can be used as a hole transport material are given.

Next, preferred examples of compounds that can be used as an electron blocking material are given.

Next, preferred examples of compounds that can be used as hole blocking materials are given.

Next, preferred compound examples that can be used as an electron transporting material are listed.

Next, preferred examples of compounds that can be used as an electron injection material will be given.

Further preferred compound examples are given as materials that can be added. For example, adding as a stabilizing material can be considered.

The organic electroluminescent device produced by the above-described method emits light by applying an electric field between the anode and the cathode of the obtained device. At this time, if the light is emitted by excited singlet energy, light having a wavelength corresponding to the energy level is confirmed as fluorescence emission and delayed fluorescence emission. In addition, in the case of light emission by excited triplet energy, a wavelength corresponding to the energy level is confirmed as phosphorescence. Since normal fluorescence has a shorter fluorescence lifetime than delayed fluorescence, the emission lifetime can be distinguished from fluorescence and delayed fluorescence.
On the other hand, phosphorescence is hardly observable at room temperature in ordinary organic compounds such as the compounds of the present invention because the excited triplet energy is unstable and converted to heat, etc., and has a short lifetime and immediately deactivates. In order to measure the excited triplet energy of a normal organic compound, it can be measured by observing light emission under extremely low temperature conditions.

The organic electroluminescence element of the present invention can be applied to any of a single element, an element having a structure arranged in an array, and a structure in which an anode and a cathode are arranged in an XY matrix. According to the present invention, an organic light-emitting device having greatly improved light emission efficiency can be obtained by including in the light-emitting layer a compound that emits delayed fluorescence and allows intramolecular proton transfer. The organic light emitting device such as the organic electroluminescence device of the present invention can be further applied to various uses. For example, it is possible to produce an organic electroluminescence display device using the organic electroluminescence element of the present invention. For details, see “Organic EL Display” (Ohm Co., Ltd.) written by Shizushi Tokito, Chiba Adachi and Hideyuki Murata. ) Can be referred to. In particular, the organic electroluminescence device of the present invention can be applied to organic electroluminescence illumination and backlights that are in great demand.

The organic light emitting device of the present invention may be an organic light emitting transistor. An organic light emitting transistor has a structure in which, for example, a gate electrode is stacked on an active layer that also serves as a light emitting layer via a gate insulating layer, and a source electrode and a drain electrode are connected to the active layer. By using a compound capable of emitting delayed fluorescence and capable of intramolecular proton transfer in the active layer of such an organic light-emitting transistor, an organic light-emitting transistor excellent in both carrier mobility and light emission characteristics can be realized.

The features of the present invention will be described more specifically with reference to synthesis examples and examples. The following materials, processing details, processing procedures, and the like can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In addition, the evaluation of the luminescence characteristics was carried out using an ultraviolet-visible near-infrared spectrophotometer (Perkin Elmer: Lambda950-PKA), a fluorescence spectrophotometer (HORIBA: FluoroMax-4), a multi-channel spectrometer (manufactured by Hamamatsu Photonics). : PMA-12C10027-01), photoexcited absolute emission quantum yield measurement device (Hamamatsu Photonics: C9920PMA-11), fluorescence lifetime measurement device (Hamamatsu Photonics: C11367-25), and streak camera (Hamamatsu Photonics) : U8167-1). In this example, fluorescence having a light emission lifetime of 100 ns or less was determined as immediate fluorescence, and fluorescence having a light emission lifetime of 0.1 μs or more was determined as delayed fluorescence.
The energy level of HOMO (Highest occupied molecular orbital) and the energy level of LUMO (Lowest unoccupied molecular orbital) are measured using an electrochemical analyzer (manufactured by BAS), cyclic voltammetry and differential pulse bontan using 0.1 mM ferrocene solution as an external standard. Measured by measurement.
From the difference Delta] E _ST excited singlet energy level (E _S1) and the lowest excited triplet energy level (E _T1) was measured as follows.

[Difference ΔE _ST between lowest excited singlet energy level (E _S1 ) and lowest excited triplet energy level (E _T1 ) in toluene or PMMA]
The difference ΔE _ST between the lowest excited singlet energy level (E _S1 ) and the lowest excited triplet energy level (E _T1 ) of the compound in toluene or PMMA is the lowest excited singlet energy level (E _S1 ) and the lowest. The excited triplet energy level (E _T1 ) was calculated by the following method and obtained by ΔE _ST = E _S1 −E _T1 .
(1) Lowest excited singlet energy level (E _S1 )
A toluene solution (concentration: 1 × 10 ⁻⁵ M) containing a measurement target compound or a PMMA film (compound concentration: 0.1 mol%, thickness 100 nm) containing a measurement target compound formed on a silicon substrate is used as a measurement sample. Prepared and measured the fluorescence spectrum of this sample at room temperature (300K). Specifically, by integrating the luminescence from immediately after the excitation light was incident to 100 nanoseconds after the incident, a fluorescence spectrum having the emission intensity on the vertical axis and the wavelength on the horizontal axis was obtained. A tangent line was drawn to the rising edge of the emission spectrum on the short wavelength side, and the wavelength value λ edge [nm] at the intersection of the tangent line and the horizontal axis was obtained. A value obtained by converting this wavelength value into an energy value by the following conversion formula was defined as _ES1 .
Conversion formula: E _S1 [eV] = 1239.85 / λedge
(2) Lowest excited triplet energy level (E _T1 )
The same sample as the lowest excitation singlet energy level (E _S1 ) was cooled to 5 [K], the excitation light (337 nm) was irradiated onto the phosphorescence measurement sample, and the phosphorescence intensity was measured using a streak camera. By integrating the luminescence from 1 millisecond after the excitation light incidence to 10 milliseconds after the incidence, a phosphorescence spectrum having the luminescence intensity on the vertical axis and the wavelength on the horizontal axis was obtained. A tangent line was drawn with respect to the rising edge of the phosphorescence spectrum on the short wavelength side, and a wavelength value λ edge [nm] at the intersection of the tangent line and the horizontal axis was obtained. A value obtained by converting this wavelength value into an energy value by the following conversion formula was defined as _ET1 .
Conversion formula: E _T1 [eV] = 1239.85 / λedge
The tangent to the short wavelength rising edge of the phosphorescence spectrum was drawn as follows. When moving on the spectrum curve from the short wavelength side of the phosphorescence spectrum to the maximum value on the shortest wavelength side of the maximum value of the spectrum, the tangent at each point on the curve toward the long wavelength side was considered. The slope of this tangent line increases as the curve rises (that is, as the vertical axis increases). The tangent drawn at the point where the value of the slope takes the maximum value was taken as the tangent to the rising edge of the phosphorescence spectrum on the short wavelength side.
The maximum point having a peak intensity of 10% or less of the maximum peak intensity of the spectrum is not included in the maximum value on the shortest wavelength side described above, and the slope value closest to the maximum value on the shortest wavelength side is the maximum value. The tangent drawn at the point taken was taken as the tangent to the rising edge of the phosphorescence spectrum on the short wavelength side.
When the sample was a toluene solution, it was measured with a phosphorescence measuring device at 77 [K].

[Difference between the lowest excited singlet energy level _{E S1} and the lowest excited triplet energy level _{E T1} in a mCBP Delta] E _ST]
difference Delta] E _ST between the lowest excited singlet energy level _{E S1} and the lowest excited triplet energy level _{E T1} of compounds in mCBP is a Delta] E _ST as the activation energy _{E a} in the Arrhenius equation, it was determined experimentally It was obtained from the slope a of the correlation diagram of T ⁻¹ and ln (k _RISC ).
That is, when both sides of the Arrhenius equation represented by the following equation (1) are converted into natural logarithms, the following equation (2) is obtained.

In the formulas (1) and (2), k represents a reaction rate constant, A represents a frequency factor, E _a represents activation energy, R represents a gas constant, and T represents an absolute temperature. Here, the gas constant R per molecule is 0.8617312 × 10 ⁻⁴ (eVK ⁻¹ ).
From equation (2), it can be seen that T ⁻¹ and ln k are expressed by a linear function with a slope of −E _a / R. Accordingly, when the slope of the correlation diagram between T ⁻¹ and lnk is a, the activation energy E _a is approximately expressed by the following equation (4).
E _a = −a × 0.8617 × 10 ⁻⁴ (4)
Here, in the reverse intersystem crossing from the excited singlet state to the excited triplet state, it is possible to see the Delta] E _ST and activation energy (the height of the potential barrier), the E _a of formula (4) Delta] E _ST The following formula (5) replaced with is established.
ΔE _ST = −a × 0.8617 × 10 ⁻⁴ (5)
In this example, a co-deposited film of the target compound and mCBP was formed so that the concentration of the target compound was 3% by weight, and the transient decay curve of the luminescence was measured at different temperatures in the range of 10 to 300K. A correlation diagram between T ⁻¹ and ln (k _RISC ) (k _RISC is the rate constant of the inverse intersystem crossing) was obtained. Led Delta] E _ST from the slope a of the correlation diagram using Equation (5).

Synthesis Example 1 Synthesis of Compound 1 3- (4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl) -1,1,5,5,9,9-hexamethyl- 13-azatriangrene) (197 mg, 0.40 mmol) and 2-bromo-4,6-diphenyl-1,3,5-triazine (140 mg, 0.45 mmol) were dissolved in 30 mL of toluene under a nitrogen atmosphere. Furthermore, after adding 55 mL of toluene, 2M sodium carbonate aqueous solution (15 mL) containing 3 drops of methyltrioctylammonium chloride and tetrakis (triphenylphosphine palladium (0)) (56 mg, 2 mol%) were added, Stir for 3 days under a nitrogen atmosphere. The aqueous layer was washed three times with toluene, the collected organic layer was dried over magnesium sulfate, and the solvent was removed by evaporation under reduced pressure. The obtained crude product was purified by silica gel column chromatography using a mixed solvent of n-hexane: dichloromethane = 3: 1 as an eluent to obtain a pale yellow solid of Compound 1.
¹ H-NMR (CDCl ₃ , 400 MHz, δ): 1.69 (s, 6H), 1.777 (s, 12H), 7.20 (t, 2H, J = 7.5 Hz), 7.43 ( dd, 2H, J = 7.5, 1.5), 7.47 (dd, 2H, J = 7.5, 1.5), 7.61 (m, 6H), 8.80 (m, 6H) ), MS (ASAP): m / z = 598 ([M + H] ⁺ ).

Synthesis Example 2 Synthesis of Compound 2

Methyl anthranilate (41.1 mL, 0.318 mol), methyl 2-iodobenzoate (13 mL, 0.909 mol), potassium carbonate (100 g, 0.727 mol), copper (I) iodide (5.89 g, 0 0.0309 mol) and copper (4.04 g, 0.0636 mol) were placed in 370 mL of diphenyl ether and stirred for 76 hours under a nitrogen atmosphere at 190 ° C. The reaction solution was filtered through Celite to remove solids, and then a liquid separation operation was performed using chloroform. The obtained organic layer was dried over sodium sulfate, sodium sulfate was removed by filtration, and then the solvent was removed from the organic layer with an evaporator to obtain a light beige solid of Intermediate 1. The obtained solid was recrystallized with ethyl acetate to obtain 98.7 g of a pale yellow solid of Intermediate 1 in a yield of 74%.

A mixture of intermediate 1 (1.00 g, 2.39 mmol) and silver (I) sulfate (0.750 g, 2.39 mmol) was suspended in 50 mL of ethanol and iodine (0.608 g, 2.39 mmol) dissolved in 100 mL of ethanol. 39 mmol) was slowly added dropwise under ice-cooling, followed by stirring at room temperature for 15 hours. The reaction solution was filtered through Celite to remove the solid, and the solvent was removed with an evaporator. The precipitated solid was purified by silica gel column chromatography using dichloromethane as an eluent to obtain a beige powder solid of Intermediate 2 in a yield of 0.450 g and a yield of 35%.

A mixture obtained by adding sodium hydroxide (0.829 g, 20.7 mmol) to intermediate 2 (0.801 g, 1.47 mmol) was added to 6.5 mL of a mixed solution of ethanol: water = 1: 1 and heated for 3 hours. After refluxing, hydrochloric acid was added dropwise to adjust the pH of the reaction solution to about 1. The precipitated solid was collected by filtration under reduced pressure and dried under reduced pressure to obtain 0.659 g of a white powder of Intermediate 3 in a yield of 89%.

Intermediate 3 (0.600 g, 1.19 mmol), thionyl chloride (2.57 mL, 35.7 mmol), and N, N-dimethylformamide 0.30 mL were placed in 45 mL of dehydrated dichloromethane and heated to reflux under a nitrogen atmosphere for 3 hours. After that, tin (IV) tetrachloride (2.52 mL, 21.4 mmol) was added, and the mixture was further heated to reflux for 18 hours. After completion of the reaction, an aqueous sodium hydroxide solution was slowly added dropwise to the reaction solution with stirring, and the mixture was stirred at room temperature for 1 hour. The obtained solid was collected by suction filtration, dried under reduced pressure, and recrystallized with nitrobenzene. As a result, a yellow solid of Intermediate 4 was obtained in a yield of 0.287 g and a yield of 54%.

Intermediate 4 (0.200 g, 0.445 mmol), 9H-carbazole (0.089 g, 0.534 mmol), copper (I) iodide (0.0169 g, 0.089 mmol), 2,2-bipyridine (0. A mixture of 0138 g, 0.089 mmol) and potassium carbonate (0.741 g, 4.45 mmol) was placed in 45 mL of o-dichlorobenzene and heated to reflux for 44 hours under a nitrogen atmosphere. After completion of the reaction, the reaction solution was cooled to about room temperature, diluted with dichloromethane, and then solids were removed by filtration under reduced pressure. The solvent was removed from the obtained filtrate by distillation under reduced pressure, and the precipitated solid was roughly purified by silica gel column chromatography using chloroform as an eluent. The crude product was purified by sublimation to obtain the target compound 2 as an orange solid in a yield of 0.0301 g and a yield of 14%.
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 9.29 (s, 2H, ArH _e ), 9.11 (dd, 2H, J = 7.5 Hz, 2.0 Hz, ArH _f ), 9.08 (Dd, 2H, J = 7.5 Hz, 2.0 Hz, ArH _h ), 8.19 (d, 2H, J = 8.0 Hz, 2.0 Hz, ArH _a ), 7.91 (dd, 2H, J = 7.5 Hz, 7.5 Hz, ArH _g ), 7.56 (d, 2 H, J = 8.0 Hz, ArH _d ), 7, 47 (ddd, 2 H, J = 7.0 Hz, 7.0 Hz, 1 0.0 Hz, ArH _c ), 7.37 (ddd, 2H, J = 7.5 Hz, 7.0 Hz, ArH _b ), MS (ASAP) m / z 488.41 [M ⁺ −H].

Synthesis Example 3 Synthesis of Compound 3

To a mixture of Intermediate 4 (0.0906 g, 0.200 mmol), triphenylaminoboronic acid (0.0589 g, 0.200 mmol), tetrakis (triphenylphosphine) palladium (0) (0.0106 g, 0.0095 mmol) After adding 5 mL of toluene, potassium carbonate (1.42 g, 103 mmol) and 5 mL of pure water were added, and the mixture was heated to reflux for 30 hours under a nitrogen atmosphere. After completion of the reaction, the reaction solution was subjected to a liquid separation operation using chloroform. The obtained organic layer was dried over magnesium sulfate, the magnesium sulfate was removed by filtration, and the solvent was removed with an evaporator. The extracted solid was roughly purified by silica gel column chromatography using chloroform as an eluent. The obtained crude product was purified by sublimation to obtain 0.0237 g of a reddish orange solid of Compound 3 in a yield of 21%.
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 9.25 (s, 2H, ArH _d ), 9.07 (ddd, 4H, J = 6.0 Hz, 6.0 Hz, 1.5 Hz, ArH _{a, c} ), 7.87 (dd, 2H, J = 7.5 Hz, 7.5 Hz, ArH _b ), 7.77 (d, 2H, J = 9.0 Hz, ArH _c ), 7.32 (dd, 4H , J = 8.0 Hz, 7.5 Hz, ArH _{h, j} ), 7.23 (d, 2H, J = 8.5 Hz, ArH _f ), 7.19 (d, 2H, J = 8.0 Hz, ArH _{g, k} ), 7.10 (dd, 2H, J = 7.5 Hz, 7.5 Hz, ArH _i ), MS (ASAP) m / z 566.18 [M ⁺ ].

(Synthesis Example 4) Synthesis of Compound 4

Intermediate 4 (0.201 g, 0.445 mmol), diphenylamine (0.0898 g, 0.534 mmol), copper (I) iodide (0.0171 g, 0.089 mmol), 2,2-bipyridine (0.0133 g, 0.089 mmol) and potassium carbonate (0.742 g, 4.45 mmol) were placed in 45 mL of o-dichlorobenzene and heated to reflux for 44 hours under a nitrogen atmosphere. After completion of the reaction, the reaction solution was cooled to about room temperature, diluted with dichloromethane, and then solids were removed by filtration under reduced pressure. The solvent was removed from the obtained filtrate by distillation under reduced pressure, and the precipitated solid was roughly purified by silica gel column chromatography using chloroform as an eluent. The obtained crude product was further purified by gel column permeation chromatography to obtain a red solid of Compound 4 in a yield of 0.0020 g and a yield of 0.9%.
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 9.03 (dd, 2H, J = 7.5 Hz, 2.0 Hz, ArH _g ), 8.98 (dd, 2H, J = 7.5 Hz, 1 .5 Hz, ArH _i ), 8, 66 (s, 2H, ArH _f ), 7.82 (dd, 2H, J = 8.0 Hz, 8.0 Hz, ArH _h ), 7.37 (dd, 4H, J = 8,0 Hz, 7.5 Hz, ArH _{b, d} ), 7.21 (d, 4 H, J = 8.0 Hz, ArH _{a, e} ), 7.18 (dd, 2 H, J = 7.5 Hz, ArH _c ), MS (ASAP) m / z 490 [M ⁺ -H].

Synthesis Example 5 Synthesis of Compound 5

Under a nitrogen stream, 0.7 g (1.34 mmol) of 2,6-dibromo-4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo [1,9] quinolidino [3 4,5,6,7-defg] acridine, 0.92 g (4.02 mmol) N, N-di (4-anisolyl) amine, 0.48 g (5.00 mmol) sodium t-butoxy and 15 mg (0 0.03 mmol) of bis (tri-t-butylphosphine) palladium (0) was heated to reflux in 50 mL of dehydrated toluene for 48 hours, and the resulting reaction solution was filtered through celite and then separated, and dried over anhydrous sodium sulfate. And the solvent was distilled off to obtain a yellow reaction mixture. The target product was purified by column chromatography (hexane / ethyl acetate) to obtain 0.9 g (1.10 mmol) of Intermediate 5 as a yellow powder in a yield of 82%.
¹ H-NMR (500 MHz, toluene d-8): δ = 7.34 (d, 2H, J = 2.5 Hz, ArH _dore ), 7.28 (d, 2H, J = 2.5 Hz, ArH _dore ) , 7.21 (d, 1H, J = 8.0 Hz, ArH _f ), 7.17 (d, 8H, J = 9.0 Hz, ArH _c ), 6.98 (s, 1H, ArH _g ), 6 .74 (d, 8H, J = 9.0 Hz, ArH _f ), 3.36 (s, 12H, ArH _a ), 1.51 (s, 12H, ArH _h ), 1.45 (s, 6H, ArH _i ).

Under a nitrogen stream, Intermediate 5 (410 mg, 0.5 mmol) was dissolved in 20 mL of tetrahydrofuran, and N-bromosuccinimide (108 mg, 0.6 mmol) dissolved in 10 mL of tetrahydrofuran was slowly added dropwise under ice cooling. After stirring for 1 hour, the mixture was stirred overnight at room temperature. A small amount of aqueous sodium thiosulfate solution was added to the obtained reaction solution, followed by liquid separation, drying over anhydrous sodium sulfate, and evaporation of the solvent to obtain a yellow reaction mixture. The target product was roughly purified by column chromatography (hexane: ethyl acetate = 3: 1), dissolved in diethyl ether, methanol was added, and the precipitated precipitate was filtered to obtain a yellow powder of Intermediate 6 in a yield of 350 mg ( 0.39 mmol), and the yield was 78%.
¹ H-NMR (500 MHz, toluene d-8): δ = 7.47 (s, 2H, ArH _f ), 7.27 (s, 4H, ArH _{d, e} ), 7.16 (d, 8H, J = 8.0 Hz, ArH _c ), 6.75 (d, 8 H, J = 9.0 Hz, ArH _b ), 3.36 (s, 12 H, ArH _a ), 1.44 (s, 6 H, ArH _h ) , 1.38 (s, 12H, ArH _g )
MS (ASAP) m / z 897.31 [M ^<+ >].

Under a nitrogen stream, intermediate 6 (160 mg, 0.17 mmol), bispinacolatodiboron (51 mg, 0.2 mmol), and potassium acetate (59 mg, 0.6 mmol) were dissolved in 20 mL of dimethylformamide, and Pd (dppf) Cl ₂ · CH ₂ Cl ₂ (4.1 mg, 0.005 mmol) was added, and the mixture was stirred at 85 ° C. for 15 hours. After completion of the reaction, the solvent was distilled off, followed by liquid separation (dichloromethane), drying over anhydrous sodium sulfate, crude purification by column chromatography (hexane: ethyl acetate = 4: 1), dissolution in diethyl ether and methanol. Was added, and the precipitated precipitate was filtered to obtain 92.0 mg (0.097 mmol) of intermediate 7 as a yellow powder in a yield of 57%.
¹ H-NMR (500 MHz, toluene d-8): δ = 8.20 (s, 2H, ArH _f ), 7.34 (d, 2H, J = 2.5 Hz, ArH _dore ), 7.26 (d , 2H, J = 2.5 Hz, ArH _dore ), 7.16 (d, 8H, J = 9.0 Hz, ArH _c ), 6.73 (d, 8H, J = 9.0 Hz, ArH _b ), 3 .36 (s, 12H, ArH _a ), 1.57 (s, 12H, ArH _g ), 1.45 (s, 6H, ArH _h ), 1.20 (s, 12H, ArH _i )
MS (ASAP) m / z 945.34 [M ⁺ ]

Under a nitrogen stream, intermediate 7 (92 mg, 0.097 mmol), 2-bromo-4,6-diphenyl-1,3,5-triazine (118 mg, 0.38 mmol) was dissolved in 20 mL of toluene, and 2 mol / L carbonic acid was dissolved. Sodium 2 mL and Pd (PPh ₃ ) ₄ (50 mg, 0.043 mmol) were added, and the mixture was heated to reflux for 36 hours. After completion of the reaction, the mixture was separated and purified by column chromatography (hexane: ethyl acetate = 4: 1) to obtain 47 mg (0.045 mmol) of yellow powdered compound 5 in 46% yield.
¹ H-NMR (500 MHz, toluene d-8): δ = 9.06 (s, 2H, ArH _k ), 8.98 (dd, 4H, J = 6.0 Hz, 2.0 Hz, ArH _j ), 7 .42, 7.04, 7.36, 7.31 (m, 10H, ArH _{d, e, f, i} ), 7.21 (dd, 8H, J = 7.0 Hz, 2.0 Hz, ArH _c ) 6.78 (d, 8H, J = 7.0 Hz, 2.0 Hz, ArH _b ), 3.39 (s, 12H, ArH _a ), 1.69 (s, 12H, ArH _g ), 1.50 (S, 6H, ArH _h )
^{MS (ASAP) m / z1050.99 [} M +]

Synthesis Example 6 Synthesis of Compound 6

A mixture of trimethyl-2,2 ′, 2 ″ -nitrilotribenzoate (3.00 g, 7.16 mmol) and silver (I) sulfate (2.23 g, 7.16 mmol) was suspended in 230 mL of ethanol and dissolved in 220 mL of ethanol. Iodine (1.82 g, 7.16 mmol) was slowly added dropwise under ice cooling, and after completion of the addition, the reaction solution was stirred at room temperature for 12 hours. The precipitated solid was purified by silica gel column chromatography using dichloromethane as an eluent to obtain a pale orange powder intermediate 8 in a yield of 1.91 g and a yield of 49%, and a pale orange powder intermediate 9 was obtained. The yield was 0.407 g and the yield was 8%.
Intermediate 8:
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 7.87 (d, 1H, J = 2.0 Hz, ArH _e ), 7.62 (dd, 1H, J = 8.0 Hz, 7.5 Hz, ArH _f ), 7.60 (d, 1H, J = 8.5 Hz, ArH _a ), 7.38 (dd, 1H, J− = 8.0 Hz, 7.5 Hz, ArH _c ), 7.12 (ddd, 2H, J = 7.5 Hz, 7.5 Hz, 3.5 Hz, ArH _b ), 7.06 (dd, 2H, J = 8.0 Hz, 2.0 Hz, ArH _d ), 6.76 (d, 1H, _{J = 8.5Hz, ArH g),} 3.43 (s, 3H, CH 3), 3.41 (s, 3H, CH 3), 3.35 (s, 3H, CH 3), MS (ASAP) m / z 545.38 [M ⁺ ].
Intermediate 9:
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 7.89 (dd, 2H, J = 5.5 Hz, 2.0 Hz, ArH _e ), 7.63 (d, 2H, J = 7.0 Hz, ArH _f ), 7.62 (d, 1H, J = 9.0 Hz, ArH _a ), 7.39 (dd, 1H, J− = 8.5 Hz, 7.5 Hz, ArH _c ), 7.15 (dd, 1H, J = 7.5 Hz, 8.0 Hz, ArH _b ), 7.06 (d, 2H, J = 9.0 Hz, ArH _d ), 6.77 (dd, 2H, J = 8.5 Hz, 9. 0 Hz, ArH _g ), 3.45 (s, 3H, CH ₃ ), 3.41 (s, 3H, CH ₃ ), 3.38 (s, 3H, CH ₃ ); MS (ASAP) m / z 671. 14 [M ⁺ ].

Sodium hydroxide (0.795 g, 19.9 mmol) was added to intermediate 9 (1.067 g, 1.59 mmol), heated under reflux in 6.7 mL of ethanol / water = 1/1 mixed solution for 3 hours, and then hydrochloric acid. Was added dropwise to adjust the pH of the reaction solution to about 2. The precipitated solid was collected by vacuum filtration and then dried under reduced pressure to obtain 0.913 g of a white powder intermediate 10 in a yield of 91%.
¹ H-NMR (500 MHz, DMSO-d6): δ = 12.75 (broad, 3H, COOH), 7.93 (broad, 2H, ArH _e ), 7.75 (broad, 3H, ArH _{a, f} ) _{, 7.47 (broad, 1H, ArH} c), 7.23 (dd, 1H, ArH b), 6.85 (b, 1H, ArH d), 6.62 (b, 2H, ArH g); MS (ASAP) m / z 629.02 [M ⁺ ], 585.03 [M ⁺ —CO ₂ ].

Thionyl chloride (2.56 mL, 35.7 mmol) and 0.30 mL of dimethylformamide were added to Intermediate 10 (0.752 g, 1.20 mmol) in 45 mL of dehydrated dichloromethane, and the mixture was heated to reflux for 3 hours under a nitrogen atmosphere. Thereafter, tin (IV) tetrachloride (2.50 mL, 21.4 mmol) was added, and the mixture was further heated to reflux for 18 hours. After completion of the reaction, an aqueous sodium hydroxide solution was slowly added dropwise with stirring, and the mixture was stirred at room temperature for 1 hour. The resulting solid was collected by suction filtration and dried under reduced pressure. Thereafter, the solid was recrystallized from nitrobenzene to obtain a yellow solid intermediate 11 in a yield of 0.336 g and a yield of 49%.
MS (ASAP) m / z 575.09 [M ^<+ >].

Intermediate 11 (0.300 g, 0.521 mmol), diphenylamine (1.13 g, 10.4 mmol), sodium tert-butoxide (2.00 g, 20.8 mmol), bisdibenzylideneacetone palladium (0.0300 g, .0. 0521 mmol) and tri-tert-butylphosphonium tetrafluoroborate (0.0151 g, 0.0521 mmol) were dehydrated by adding dehydrated toluene (12 mL), and then heated to reflux under a nitrogen atmosphere for a period of time. After completion of the reaction, a liquid separation operation was performed, extraction was performed with dichloromethane, and the organic layer was dried over sodium sulfate. The sodium sulfate was removed by filtration, and the solvent was removed with an evaporator. The precipitated solid was roughly purified by silica gel column chromatography of distillate dichloromethane. The obtained solid was purified by sublimation to obtain 0.0864 g of a black purple solid compound 6 in a yield of 25%.
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 8.96 (dd, 2H, J = 7.5 Hz, ArH _b ), 8.96 (dd, 2H, J = 7.5 Hz, ArH _b ), ( dd, 1H, J = 7.5 Hz, ArH _a ), 7.34 (dd, 8H, J = 7.5 Hz, 8.0 Hz, ArH _{e, g} ), 7.19 (d, 8H, J = 8. 0 Hz, ArH _{d, h} ), 7.15 (dd, 4H, J = 7.5 Hz, 7.5 Hz, ArH _f ), MS (ASAP) m / z 657.21 [M ⁺ ].

(Synthesis Example 7) Synthesis of Compound 7

A mixture of trimethyl-2,2 ′, 2 ″ -nitrilotribenzoate (3.01 g, 7.16 mmol) and silver (I) sulfate (5.40 g, 21.5 mmol) is suspended in 150 mL of ethanol and dissolved in 300 mL of ethanol. Iodine (6.69 g, 21.5 mmol) was slowly added dropwise under ice-cooling, and the reaction solution was stirred for 15.5 hours at room temperature after completion of the dropwise addition. The precipitated solid was purified by silica gel column chromatography using dichloromethane as an eluent to obtain 1.16 g of intermediate 12 as a beige powder solid in a yield of 20%.
MS (ASAP) m / z 545.38 [M ^<+ >].

Sodium hydroxide (0.795 g, 19.9 mmol) was added to intermediate 12 (1.27 g, 1.59 mmol), heated under reflux in 6.7 mL of ethanol / water = 1/1 mixed solution for 3 hours, and then hydrochloric acid. Was added dropwise to adjust the pH of the reaction solution to about 2. The precipitated solid was collected by filtration under reduced pressure and dried under reduced pressure to obtain 1.18 g of a white powder intermediate 13 in a yield of 98%.
^{MS (ASAP) m / z755.00 [} M +], 710.99 [M + -CO 2].

Thionyl chloride (2.56 mL, 35.7 mmol) and 0.30 mL of dimethylformamide were added to intermediate 13 (0.900 g, 1.19 mmol) in 50 mL of dehydrated dichloromethane, and the mixture was heated to reflux for 3 hours under a nitrogen atmosphere. Thereafter, tin (IV) tetrachloride (2.50 mL, 21.4 mmol) was added, and the mixture was further heated to reflux for 18 hours. After completion of the reaction, an aqueous sodium hydroxide solution was slowly added dropwise with stirring, and the mixture was stirred at room temperature for 1 hour. The resulting solid was collected by suction filtration and dried under reduced pressure. Thereafter, the solid was recrystallized from nitrobenzene to obtain a yellow solid intermediate 14 in a yield of 0.553 g and a yield of 66%.
MS (ASAP) m / z 700.99 [M ^<+ >].

Intermediate 14 (0.450 g, 0.642 mmol), diphenylamine (3.25 g, 19.3 mmol), sodium tert-butoxide (3.70 g, 38.5 mmol), bisdibenzylideneacetone palladium (0.0367 g, 0. 0642 mmol) and tri-tert-butylphosphonium tetrafluoroborate (0.0186 g, 0.0642 mmol), dehydrated toluene (15 mL) was added thereto, and the mixture was deaerated and heated to reflux for 19 hours under a nitrogen atmosphere. After completion of the reaction, a liquid separation operation was performed, extraction was performed with dichloromethane, and the organic layer was dried over sodium sulfate. The sodium sulfate was removed by filtration, and the solvent was removed with an evaporator. The precipitated solid was roughly purified by silica gel column chromatography of distillate dichloromethane. The obtained solid was purified by sublimation to obtain 0.0910 g of a black purple solid compound 7 in a yield of 17%.
¹ H-NMR (500 MHz, CDCl ₃ ): δ = 8.57 (s, 6HArH _f ), 7.32 (dd, 12H, J = 8.0 Hz, 7.5 Hz, ArH _{b, d} ), 7.17 (D, 12H, J = 7.5 Hz, ArH _{a, e} ), 7.13 (dd, 12H, J = 7.5 Hz, 7.5 Hz, ArH _c ), MS (ASAP) m / z 825.16 [M ⁺ ].

Example 1 Production and Evaluation of Organic Photoluminescence Device Using Compound 1 A toluene solution of Compound 1 (concentration: 1.0 × 10 ⁻⁵ mol / L) was prepared in a glove box under an Ar atmosphere.
In addition, a thin film (polymer film) made of Compound 1 and polymethylmethacrylate was formed to a thickness of 200 nm on a quartz substrate by a spin coating method to obtain an organic photoluminescence element. At this time, the concentration of Compound 1 was 0.1 mol% or 10 mol%. In addition, in the polymer film in which the concentration of Compound 1 is 0.1 mol%, Compound 1 is present in a uniformly dispersed state, and in the polymer film in which the concentration of Compound 1 is 10 mol%, aggregation of Compound 1 is observed. It was.
Furthermore, a thin film (single film) of Compound 1 having a thickness of 100 nm was formed on a quartz substrate by a vacuum deposition method under a vacuum degree of 4 × 10 ⁻⁴ Pa or less to obtain an organic photoluminescence device.
Separately, Compound 1 and DPEPO were deposited from different deposition sources on a quartz substrate by a vacuum deposition method under a vacuum degree of 4 × 10 ⁻⁴ Pa or less, and the concentration of Compound 1 was 0.5 wt%. A thin film (dope film) of 2% by weight or 10% by weight was formed to a thickness of 40 nm to obtain an organic photoluminescence device.
Further, a doped film containing Compound 1 was formed in the same manner as described above except that mCP or mCBP was used instead of DPEPO to obtain an organic photoluminescence device.

Compound 1 was subjected to electrochemical measurement in a state of being uniformly dissolved in toluene (homogeneous system). As a result, the HOMO level was −5.16 eV and the LUMO level was −2.13 eV. In addition, the HOMO level obtained from the photoelectron spectroscopy and absorption spectrum absorption edge performed on the vapor-deposited single film (aggregation system) of Compound 1 in the atmosphere was −5.51 eV, and the LUMO level was −2.81 eV. It was. Further, from the fluorescence spectrum and phosphorescence spectrum of the toluene solution of Compound 1, the excited singlet energy level E _S1 of Compound ₁ is 2.884 eV, the excited triplet energy level E _T1 is 2.758 eV, and the excited singlet energy level. difference Delta] E _ST's place and excited triplet energy level was estimated to 0.128EV.
In addition, the light emission characteristics of the toluene solution, the polymer film, the single film and each doped film containing Compound 1 prepared in Example 1 were evaluated. Table 1 shows the photoluminescence quantum yield (PL quantum yield) measured in the air or in an argon atmosphere. The emission maximum wavelength of the toluene solution of Compound 1 was 460 nm, and the emission maximum wavelength of the single film of Compound 1 was 490 nm.

As shown in Table 1, the toluene solution containing the compound 1, the polymer film, and each of the doped films all showed higher PL quantum yields in the argon atmosphere than in the atmosphere. This is presumably because the deactivation of triplet excitons by oxygen was suppressed under an argon atmosphere. This suggests that the fluorescence emission process of Compound 1 includes an inverse intersystem crossing process from the excited triplet state T ₁ to the excited singlet state S ₁ .
Moreover, when the transient decay curve of light emission was measured at 300 K for the polymer film containing Compound 1, the single film, and each doped film, delayed fluorescence could be observed for all. Furthermore, when the measurement was performed in the range of 300 to 10K, temperature dependence was observed in which the light emission lifetime increased with increasing temperature.
From these results, it was found that Compound 1 is a thermally activated delayed fluorescent material that emits light through reverse intersystem crossing from the excited triplet state T ₁ to the excited singlet state S ₁ .

Examples 2 to 4 Preparation and Evaluation of Organic Photoluminescence Device Using Compounds 2 to 4 Compounds 2 to 4, 6, and 7 were used instead of Compound 1, and only mCBP was used as the host material for the doped film. Except for the above, a toluene solution containing the compounds 2 to 4, a polymer film and a dope film were prepared in the same manner as in Example 1 to obtain an organic photoluminescence device. However, the concentrations of the compounds 2 to 4, 6, and 7 were 1.0 × 10 ⁻⁵ mol / L in the toluene solution, 0.1 mol% in the polymer film, and 3 wt% in the dope film.

Example 5 Production and Evaluation of Organic Photoluminescence Device Using Compound 5 A toluene solution of compound 5 (concentration 1.0 × 10 ⁻⁵ mol / L) and a cyclohexane solution (concentration 1.) in a glove box under an Ar atmosphere. 0 × 10 ⁻⁵ mol / L) was prepared and used as an organic photoluminescence device.

Comparative Example 1 Preparation and Evaluation of Toluene Solution of Comparative Compound 1 A toluene solution (concentration: 1.0 × 10 ⁻⁵ mol / L) of Comparative Compound 1 was prepared in a glove box under an Ar atmosphere, and used as a comparative sample.

Table 2 shows HOMO levels and LUMO levels measured in toluene for the compounds 2 to 4, 6, 7 and comparative compound 1, and the toluene solutions prepared in Examples 2 to 4, 6, 7 and comparative example 1 indicates a polymer film, the excitation of the doped film singlet energy level E _S1, the excited triplet energy level E _T1 and these energy difference Delta] E _ST Table 3.

Also, the light emission characteristics of each toluene solution, each polymer film, each dope film prepared in Examples 2 to 7 and Comparative Example 1, and the cyclohexane solution prepared in Example 5 were evaluated. For each toluene solution and cyclohexane solution, PL quantum yield and emission lifetime measured in the air or in the absence of oxygen are shown in Table 4, and for each polymer film and each dope, the PL was measured in the air or in the absence of oxygen. Table 5 shows the quantum yield and the emission lifetime measured in the absence of oxygen. Here, “in the absence of oxygen” means after nitrogen bubbling in a toluene solution or cyclohexane solution, and in an argon atmosphere in a polymer film and a dope film.

As shown in Tables 4 and 5, each solution containing compounds 2 to 5, each polymer film containing compounds 2 to 4 and each doped film were higher in PL quantum yield than in the atmosphere in the absence of oxygen. A delayed fluorescence component on the order of microseconds was observed. Further, from the delayed fluorescence lifetime of the toluene solution shown in Table 4, there was a tendency for the delayed fluorescence lifetime to increase by removing oxygen. These results are thought to be due to the suppression of the deactivation of triplet excitons by oxygen. For compounds 2 to 5 as well, in the fluorescence emission process, from the excited triplet state T ₁ to the excited singlet state S 1 It was suggested that the reverse intersystem crossing process to ₁ is involved. Further, when the transient decay curve of light emission was measured at 300 to 10 K for each polymer film containing each of compounds 2 to 5 and each doped film, temperature dependence in which the light emission lifetime increased with an increase in temperature was recognized. From these results, it was confirmed that the compounds 2 to 5 are also thermally activated delayed fluorescent materials that emit light through the reverse intersystem crossing from the excited triplet state T ₁ to the excited singlet state S ₁ .

(Example 6) Production of an organic electroluminescence device using Compound 1 (0.5 wt%) and DPEPO as a light emitting layer On a glass substrate on which an anode made of indium tin oxide (ITO) having a thickness of 100 nm was formed Further, each thin film was laminated at a vacuum degree of 4.0 × 10 ⁻⁴ Pa by a vacuum deposition method. First, NPD was formed on ITO with a thickness of 30 nm, and TCTA was formed thereon with a thickness of 20 nm. Next, Compound 1 and DPEPO were co-evaporated from different vapor deposition sources to form a 40 nm thick layer as a light emitting layer. At this time, the concentration of Compound 1 was 0.5% by weight. Next, DPEPO was formed to a thickness of 10 nm, and TPBi was formed thereon to a thickness of 30 nm. Further, lithium fluoride (LiF) was formed to a thickness of 0.8 nm, and then aluminum (Al) was vapor-deposited to a thickness of 80 nm to form a cathode, whereby an organic electroluminescence element was obtained.

(Examples 7 and 8) Preparation of an organic electroluminescence device using Compound 1 (2% by weight or 10% by weight) and DPEPO in the light emitting layer The concentration of Compound 1 in the light emitting layer was changed to 2% by weight or 10% by weight. An organic electroluminescence element was produced in the same manner as in Example 6 except that.

(Example 9) Preparation of organic electroluminescence device in which two light emitting layers having different concentrations of compound 1 were formed Instead of forming a light emitting layer in which the concentration of compound 1 was 0.5% by weight, the concentration of compound 1 was A light emitting layer having a thickness of 10% by weight was formed to a thickness of 20 nm, and a light emitting layer having a concentration of Compound 1 having a concentration of 2% by weight was formed to a thickness of 20 nm to form a light emitting layer having a two-layer structure. An organic electroluminescence element was produced in the same manner as in Example 6 except that.

(Examples 10 and 11) Preparation of an organic electroluminescent device using Compound 1 (2 wt% or 10 wt%) and mCP in the light emitting layer Using mCP instead of DPEPO, the concentration of Compound 1 in the light emitting layer was 2 wt% An organic electroluminescence device was produced in the same manner as in Example 6 except that the content was changed to% or 10% by weight.

(Example 12) Preparation of an organic electroluminescence device using Compound 1 (2 wt%) and mCBP as a light emitting layer Each thin film was laminated | stacked by the vacuum evaporation method by the same vacuum degree as Example 1. FIG. First, HAT-CN was formed to a thickness of 10 nm on ITO, and Tris-PCz was formed to a thickness of 30 nm thereon. Next, Compound 1 and mCBP were co-evaporated from different vapor deposition sources to form a 30 nm thick layer as a light emitting layer. At this time, the concentration of Compound 1 was 2% by weight. Next, T2T was formed to a thickness of 10 nm, and BPy-TP2 was formed thereon to a thickness of 40 nm. Further, lithium fluoride (LiF) was formed to a thickness of 0.8 nm, and then aluminum (Al) was vapor-deposited to a thickness of 80 nm to form a cathode, whereby an organic electroluminescence element was obtained.

(Example 13) Production of organic electroluminescence device using compound 1 (10 wt%) and mCBP in light emitting layer The same manner as in Example 12 except that the concentration of compound 1 in the light emitting layer was changed to 10 wt%. Thus, an organic electroluminescence element was produced.

(Examples 14 to 16) Preparation and evaluation of organic electroluminescence device using compounds 2 to 4 Compound 2 was used instead of compound 1, and the concentration of compound 2 in the light emitting layer was changed to 3% by weight. An organic electroluminescence device was produced in the same manner as in Example 12.

Table 6 shows the maximum external quantum efficiencies obtained from the external quantum efficiency-current density characteristics of the organic electroluminescence devices produced in Examples 6 to 12. In the element configuration column of Table 6, diagonal lines indicate the boundaries between layers, and numerical values in units of nm in parentheses indicate the thickness of the layers.

As shown in Table 6, by using compounds 1 to 4, an organic electroluminescence device having high luminous efficiency could be realized. In addition, the CIE chromaticity coordinate of light emission of the organic electroluminescence device using the compound 2 (Example 14) was (0.248, 0.611).

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Cathode

Claims (40)

1. A compound having a structure represented by the following general formula (1).
   

   

   [In the general formula (1), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Y ¹ to Y ³ are each independently a substituted or unsubstituted methylene group (C (R ¹⁰ ) (R ¹¹ ); R ¹⁰ and R ¹¹ each independently represents a hydrogen atom or a substituent), a carbonyl group (C═ O), a thiocarbonyl group (C═S), a substituted or unsubstituted imino group (N (R ¹² ); R ¹² represents a hydrogen atom or a substituent), an oxygen atom, a sulfur atom, or a sulfonyl group (SO ₂ ). Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
2. The compound according to claim 1, wherein Z in the general formula (1) is a nitrogen atom.
3. The compound according to claim 1 or 2, wherein Y ¹ to Y ³ in the general formula (1) are a carbonyl group or a dialkylmethylene group.
4. The compound according to any one of claims 1 to 3, wherein R ² in the general formula (1) is a substituent.
5. The compound according to claim 4, wherein R ² in the general formula (1) is a donor group.
6. The compound according to claim 4, wherein R ² in the general formula (1) is an acceptor group.
7. The compound according to any one of claims 4 to 6, which can form a hydrogen bond between R ¹ and R ² in the general formula (1).
8. The may form a hydrogen bond is also general formula in (1) between the R ² and R ^3, A compound according to claim 7.
9. The compound according to any one of claims 1 to 8, which has a line symmetry axis in the molecule.
10. The compound according to any one of claims 1 to 9, which is represented by the following general formula (2).
    

    

    [In the general formula (2), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. R ¹¹ to R ¹⁶ each independently represents a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
11. The compound according to claim 10, wherein R ² in the general formula (2) is a substituted or unsubstituted heteroaryl group.
12. The compound according to claim 11, wherein the heteroaryl group contains a nitrogen atom as a ring skeleton constituent atom.
13. The compound according to claim 12, wherein at least one of the atoms constituting the ring skeleton adjacent to the atom involved in bonding of the heteroaryl group is a nitrogen atom.
14. The compound according to claim 13, wherein R ¹ in the general formula (2) is a hydrogen atom.
15. The compound according to claim 12, wherein each of the ring skeleton constituent atoms adjacent to the atom involved in the bonding of the heteroaryl group is a nitrogen atom.
16. The compound according to claim 15, wherein the heteroaryl group is a substituted or unsubstituted triazinyl group.
17. The compound according to claim 16, wherein the heteroaryl group is a substituted or unsubstituted diaryltriazinyl group.
18. The compound according to any one of claims 15 to 17, wherein R ¹ and R ³ in the general formula (2) are hydrogen atoms.
19. The method according to any one of claims 11 to 18, wherein at least one of R ⁴ to R ⁶ and at least one of R ⁷ to R ^{9 in} the general formula (2) is a group containing a diarylamino structure or a carbazole ring. The described compound.
20. The compound according to claim 19, wherein R ⁵ and R ⁸ in the general formula (2) are a group containing a diarylamino structure or a carbazole ring.
21. 21. At least one of R ⁴ to R ⁶ and at least one of R ⁷ to R ^{9 in} the general formula (2) is a group having a structure represented by the following general formula (4). The compound according to any one of the above.
    

    

    [In the general formula (4), R ²¹ to R ³⁰ each independently represents a hydrogen atom or a substituent. R ²⁵ and R ²⁶ may be linked to each other to form a single bond or a linking group. L represents a single bond or a substituted or unsubstituted arylene group. * Indicates a binding position. ]
22. The compound according to claim 21, wherein R ²⁵ and R ²⁶ in the general formula (4) are not linked to each other.
23. The compound according to claim 21 or 22, wherein at least one of R ²³ and R ²⁸ in the general formula (4) is a substituent.
24. The compound according to any one of claims 21 to 23, wherein L in the general formula (4) is a single bond.
25. The compound according to any one of claims 10 to 24, wherein R ¹¹ to R ¹⁶ in the general formula (2) are each independently a substituted or unsubstituted alkyl group.
26. The compound according to claim 25, wherein R ¹¹ to R ¹⁶ in the general formula (2) are methyl groups.
27. The compound according to any one of claims 1 to 9, which is represented by the following general formula (3).
    

    

    [In the general formula (3), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
28. The compound according to claim 27, wherein at least one of R ¹ to R ⁹ in the general formula (3) is a donor group.
29. The compound according to claim 27 or 28, wherein R ² in the general formula (3) is a group containing a diarylamino structure or a carbazole ring.
30. The compound according to any one of claims 27 to 29, wherein at least one of R ¹ to R ⁹ in the general formula (3) is a group having a structure represented by the following general formula (4).
    

    

    [In the general formula (4), R ²¹ to R ³⁰ each independently represents a hydrogen atom or a substituent. R ²⁵ and R ²⁶ may be linked to each other to form a single bond or a linking group. L represents a single bond or a substituted or unsubstituted arylene group. * Indicates a binding position. ]
31. The compound according to claim 30, wherein R ²⁵ and R ²⁶ in the general formula (4) are not linked to each other.
32. The compound according to claim 30, wherein R ²⁵ and R ²⁶ in the general formula (4) are linked to each other to form a single bond.
33. The compound according to any one of claims 30 to 32, wherein L in the general formula (4) is a substituted or unsubstituted phenylene group.
34. The compound according to any one of claims 30 to 32, wherein L in the general formula (4) is a single bond.
35. The compound according to any one of claims 30 to 34, wherein R ² in the general formula (3) is a group represented by the general formula (4).
36. The compound according to any one of claims 1 to 35, which emits delayed fluorescence.
37. A light emitting material comprising a compound having a structure represented by the following general formula (1).
    

    

    [In the general formula (1), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Y ¹ to Y ³ are each independently a substituted or unsubstituted methylene group (C (R ¹⁰ ) (R ¹¹ ); R ¹⁰ and R ¹¹ each independently represents a hydrogen atom or a substituent), a carbonyl group (C═ O), a thiocarbonyl group (C═S), a substituted or unsubstituted imino group (N (R ¹² ); R ¹² represents a hydrogen atom or a substituent), an oxygen atom, a sulfur atom, or a sulfonyl group (SO ₂ ). Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
38. The organic light emitting element containing the compound which has a structure represented by following General formula (1).
    

    

    [In the general formula (1), R ¹ to R ⁹ each independently represents a hydrogen atom or a substituent, and at least one of R ¹ to R ⁹ is a substituent. Y ¹ to Y ³ are each independently a substituted or unsubstituted methylene group (C (R ¹⁰ ) (R ¹¹ ); R ¹⁰ and R ¹¹ each independently represents a hydrogen atom or a substituent), a carbonyl group (C═ O), a thiocarbonyl group (C═S), a substituted or unsubstituted imino group (N (R ¹² ); R ¹² represents a hydrogen atom or a substituent), an oxygen atom, a sulfur atom, or a sulfonyl group (SO ₂ ). Z represents a nitrogen atom, a boron atom, or a phosphine oxide group (P = O). ]
39. The organic light-emitting device according to claim 38, wherein the device is an organic electroluminescence device.
40. 40. The organic light emitting device according to claim 38 or 39, which emits delayed fluorescence.
    
    

Images